Project Summary: The goal of this research is to develop a computational platform that simulates light transport in a system that considers explicitly the structural and compositional complexity of tissue. This virtual tissue simulator (VTS) for radiative transport will allow representations of tissues that are either user-defined using 'primitive1 tissue elements (e.g., cells, matrix, vasculature) or aided through images provided by modalities such as histology, CT or MRI. The main input module to the VTS will require this tissue definition along with a user-defined configuration for optical source(s) and detector(s). The computational engine of the VTS will utilize a Monte Carlo (MC) simulation of radiative transport. The VTS output module will provide displays of the spatial distributions of the internal absorption and scattering, light distributions between source(s) and detector(s), and time/spatially-resolved reflectance/transmittance using advanced MC techniques (e.g. perturbation/differential MC, coupled forward-adjoint MC, etc.). Comparison of these results with experimental measurements across spatial scales will validate the models employed. The candidate is an applied mathematician whose expertise lies in Monte Carlo methods for radiative transport. Her career goal is to be capable of leading an independent research program in computational biophotonics and play a critical role in multi-investigator efforts in which computational biophotonics is an integral part. The candidate will be mentored jointly by Profs. Bruce Tromberg and Vasan Venugopalan, who are PI and co-Pi of the Laser Microbeam and Medical Program; a NIH P41 National Biotechnology Resource. The candidate's proposed research activities have strong synergy with the mentors' longstanding research activities in laser-tissue interactions, radiative transport, and optical diagnostics, and microscopy. The proposed research training program will advance her knowledge of cell biology and tissue physiology and provide hands-on experience with optical technologies to characterize tissue on micro- and mesoscopic scales in both laboratory and clinical settings. These training activities will ensure that the VTS is developed in a context where validation is provided via experimental measurements in tissue phantoms and engineered tissues. Relevance: The VTS will provide the Biomedical Optics community a much needed tool to realistically simulate the impact of mesoscopic and microscopic tissue properties and organization on light-tissue interactions. This tool will enable researchers the ability to examine the impact of tissue transformations on optical signals and thereby provide critical guidance for improved design of optical probes/instrumentation used for therapeutic/diagnostic applications.